Mammalian body temperature is normally controlled by an internal autonomic regulatory system referred to herein as the thermoregulatory system. One important effector in this system is by controlled by blood flow to specialized skin areas of the body at non-hairy skin surfaces (i.e., at the palms, soles of the feet, cheeks/nose regions). Subcutaneous to these areas, there are unique anatomical vascular structures called venous plexuses. These structures serve to deliver large volumes of blood adjacent the skin surface. By this delivery of blood, significant heat transfer is enabled for the maintenance of internal organs within a functional temperature range. Blood is permitted to pass through the venous plexuses “radiator” structures by way of arterio venous anastamosis, or AVAs that gate or control the arterial input side of the venous plexuses. Thus, the AVA's serve an integral part of the heat transfer system, providing thermoregulatory control. Together, the AVA's and venous plexuses comprise a body's relevant heat exchange vasculature.
Normally, when body and/or environmental temperatures are high, dilation of certain blood vessels favors high blood flow to the noted heat exchange surfaces, thus increasing heat loss to the environment and reduction in the deep body core region temperature. As environmental and/or body temperatures fall, vasoconstriction reduces blood flow to these surfaces and minimizes heat loss to the environment.
There are situations, however, in which it would be desirable to manipulate the transfer of heat across skin surfaces to lower and/or raise the core body temperature. Such core body cooling or heating would be useful in a number of applications, including therapeutic treatment regimens and as a component of improving athletic or industrial performance.
The present invention is geared to improvement implementation of these goals. It does so in various ways by specifically taking natural vasoconstriction tendencies into account in order that unintended vasoconstriction (during an intended procedure) will not adversely effect blood flow in the region of a heat transfer surface so as to prevent adequate heat transfer.